Known crystal structures may be utilized to derive information about the intermolecular forces which hold the molecules together. The molecular packing analysis method has been used extensively for this purpose to obtain nonbonded potential parameters for carbon and hydrogen atoms in hydrocarbons. A further extension to include nitrogen and oxygen interactions is proposed, with the project eventually to consider hydrogen bonds also. Coulombic point charges on the atoms, as well as the usual repulsions and dispersion force attractions, are necessary even in hydrocarbons. Those coulombic effects will, no doubt, become more important for nitrogen and oxygen interactions.